Patent Number: 6,167,747

Title: Apparatus for detecting hydrocarbon using crystal oscillators within fuel dispensers

Abstract: A vapor recovery system is disclosed that utilizes a crystal oscillator for sensing the presence of hydrocarbon in the vapor emissions emanating from a fuel tank during refueling. The crystal oscillator is coated with a layer of material having a sensitivity for hydrocarbon. In response to any interaction between the coating layer and hydrocarbon, the crystal oscillator experiences a shift in its oscillation frequency relative to the fundamental resonance frequency. The frequency shift is representative of the hydrocarbon concentration in the vapor emissions. A control signal based on the frequency shift is generated and then used to adjust the operating speed of the vapor pump.

Inventors: Koch; Wolfgang H. (Batavia, IL), Brown; Arthur R. (Warrenville, IL)

Assignee: Tokheim Corporation

International Classification: B67D 5/01 (20060101); B67D 5/04 (20060101); G01N 29/02 (20060101); G01N 29/036 (20060101); B67D 005/378 (); B65B 001/04 (); G01N 029/02 ()

Expiration Date: 01/02/2018